<html>
<head>
    <meta charset="UTF-8">
    <title></title>
    <script type="text/javascript">
        function disp_prompt() {
            var name = prompt("Please enter yourname", "")
            if (name != null && name != "") {
                document.write("Hello " + name + "!")
            }
        }
    </script>
</head>
<body>
<input type="button" onclick="disp_prompt()"
       value="请点击"/>
</body>
</html>